Sand-blast apparatus.



L. SAUER. SAND BLAST APPARATUS. APPLIOATIONTILED D1104.I 1911 Patented July16,1912. V

W111] a '5 5 zw LUDWIG SAUER, OF KITZINGEN, GERMAN Y.

STAND-BLAST APPARATUS.

To all WhOmfllt may concern:

Be it known that I, LUDWIG SAUER, a subject of the King of Bavaria, German Empire, residing at Kitzingen-on-the-Main, in said 'Empire, have invented new and useful Improvements in Sand-l3last Apparatus; and I do declare the following to be a full,

clear, and exact description of the inven-- tion, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to sand blast apparatus such as is used for cleaning castings, removing rust from large structures such as railway stations, bridges, ships hulls and the like.

The invention has for object to provide an improved apparatus by means of which the sand blast can be produced at a fixed stas tion and conducted with undiminished force to great distances without the piping through which the blast is transmitted becoming scoured or blocked up. This object is at tained by means of the invention which consists substantially in dividing the compressed air into two streams one of which flows in a straight line and the other in a helical path, the sand being supplied to the blast moving in the helical path.

One constructional form of the improved sand blast apparatus is shown in Figure 1 in sectional elevation in the accompanying drawing, and Fig. 2 is a detail vertical central section of the central tube of the apparatus.

i It comprisesa sand box a the pressure in which is that of the compressed air, the said box having a conical or hopper shaped floor Z) to which sand is continuously supplied in any known manner. A pipe 0 coming from the compressed air supplyis connected to the bottom of the hopper where it leads into a pipe or channel (Z from which the sand air mixture is conducted to the working place. According to this invention a tube f open at both ends is arranged in the compressed air pipe 0 and in the annular space between the tube 7 and the internal wall of the pipe 0 is provided a helical rib g. Distributed over the length of the helical rib g or in proximity to the lower end of the helical rib and central tube f, the compressed air pipe c has openings h which can be closed or partially or -'fully opened by rotating orsliding a sleeve is provided with corresponding open- 9 Specification of Letters Patent.

Patented July 16,1912.

Application filed December 4, 191-1. Serial 110., 663,914.

ings z and.einbracingthe vertical portion of the pipe 0.

This apparatus (poi-ates as follows, The compressed air, which is supplied to i the channel formed between the tube and helical rib r through the pipe c and to the ceiltral tube f is distributed v,partly over the screw surface 9 and partly to the straight tube f. The portion of the air which flows through the helical space between the screw surface g'and the sides of the tubes-f and e is constrained to execute a helical motion in,

the said space. The outer air current moving in this manner, shortly before it leaves the screw surface 72 in the sleeve Z1 and draws the sand through to participate in the motion so that the sand air mixture formed here also advances in a helical path after leaving the screw SUP-- face. Simultaneously the air current issu ing from the lower end of the straight pipe f. blows through the outer whirling envelop of sand and air, and possessing a greater velocity than the latter, it draws the sand therefrom toward the middle and carries the sand to great distances to the working place,- without the sand being able to come in contact with the walls of the conducting piping, or to collect in the bends therein. This result is explained by the fact that the outer air current whirling in a helical path is robbed of its sand and forms an air cushion flows past the openings between the pipe walls and the inner sand saturated blast or jet flowing in a straight line. The friction .in the piping is. thus limited to the greatest extent, wear and clogging up of the piping prevented, and the possibility created of transporting the sand from a central station tofconsiderable distances to the working place, by means of the compressed air.

Having thus described my invention, I. claim and desire to secure by Letters Patent:-

1. An improved sand-blast apparatus comprising a comprcssed-air supply-pipe, a straight central tube in said supply-pipe, a helical rib in the space between the central tube and the supply-pipe, and means for supplying sand into the channel formed by the helicahribwherebythe compressed airsupply is divided into two streams one fiOW- ing in a straight line and the other in a helical path.

2. An improved sand-blast apparatus comprisinga compressed-air supplyepipe, a no straight central tube in said supply-pipe, a helical rib located-in the space'between' the straight tube and the inner wall of the air --supply-'.pipe, a hopper containing sand, and

means for supplying sand from said hopper into the helical channel formed between the air supply-pipe and the central tube in the same.

3. An improved sand-blast apparatus comprising a compressed-air supplyplpe having openings in its lower end, a straight central tube in said supply-pipe, a helical rib located in the space between the straight tube and the inner Wall of the air supply- 

